Repeta D J, Simpson D J, Jorgensen B B, Jannasch H W
Department of Chemistry, Woods Hole Oceanographic Institution, Massachusetts 02543, USA.
Nature. 1989 Nov 2;342(6245):69-72. doi: 10.1038/342069a0.
The contribution of anoxygenic photosynthesis to carbon cycling in the Black Sea, the world's largest body of anoxic marine water, has been vigorously investigated and debated for over four decades. Penetration of light into the sulphide-containing deep water may result in a zone of anaerobic primary production by photosynthetic bacteria. We report here the results of analyses of photosynthetic pigments in samples of suspended particulate matter collected from two stations in the western basin of the Black Sea. Our data demonstrate high concentrations of a bacterio-chlorophyll at the chemocline, and thus the potential for anoxygenic photosynthesis as a component of primary production in the carbon cycle of the Black Sea. More than 95% of the pigments in the bacteriochlorophyll-maximum are accounted for by a series of aromatic carotenoids and bacteriochlorophylls-e, including a previously unreported geranyl ester of 4-i-butyl bacteriochlorophyll-e. The distribution of pigments is characteristic of the obligate phototrophs Chlorobium phaeobacteroides and C. phaeovibriodes. Total depth-integrated bacteriochlorophyll at one station exceeded total chlorophyll-a in the overlying oxygenated portion of the euphotic zone. We suggest that anoxygenic photosynthesis is a relatively recent phenomenon in the Black Sea initiated by shallowing of the chemocline over the past decade and development of an anoxic layer devoid of O2 and H2S.
在过去四十多年里，对世界上最大的缺氧海——黑海的无氧光合作用对碳循环的贡献进行了大量研究和激烈辩论。光线穿透到含硫化物的深水层中，可能会形成光合细菌进行厌氧初级生产的区域。我们在此报告对从黑海西部盆地两个站点采集的悬浮颗粒物样本中光合色素的分析结果。我们的数据表明，在化学跃层处细菌叶绿素浓度很高，因此无氧光合作用有可能成为黑海碳循环初级生产的一个组成部分。细菌叶绿素含量最高处超过95%的色素是由一系列芳香类胡萝卜素和细菌叶绿素e构成，其中包括一种此前未报道的4 -异丁基细菌叶绿素e的香叶酯。色素的分布是专性光合细菌——褐杆菌绿菌和褐弧菌绿菌的特征。在一个站点，深度积分细菌叶绿素总量超过了光合层上部含氧区域的叶绿素a总量。我们认为，无氧光合作用是黑海相对较新出现的现象，是由过去十年化学跃层变浅以及无氧层（不含氧气和硫化氢）的形成引发的。
